SM9-based Anonymous Search over Encrypted Data

To prop standardized commercial cryptography up, a series of commercial cryptography standards (SM) have be announced. There exist SM-based constructions for digital signature and encryption up to date while it is still unknown how to design SM-based searchable encryption (SE) for better data retrieval. If applying SM9 (which fits SE structure) into traditional SE schemes, it incurs data source leakage due to insider attacks. Harmonizing SM9 and searchable encryption is, therefore, a challenge especially the privacy issue is considered. In our paper, we first explore the privacy of sender in SE and construct a newly cryptographic primitive named Privacy-preserving Encryption with Sender Search (PES) via a combination of identity-based encryption (IBE). With an idea of additionally introducing the sender's secret key, PES can resist the sender identity leakage. We present an SM9-based Anonymous Searchable Encryption (SM9-based AES) scheme on top of PES and prove its security in the formal security models. Through algorithm implementation, the proposed SM9-based AES is demonstrated to be cost-efficient with reasonable computation time.